These weaknesses was exploited by the Habsburgs and Swedes during the Thirty Years' War and the Hohenzollerns were unable to prevent Brandenburg and Prussia from being razed by the two opposing sides. The people were decimated, as were their representative committees, the Estates. Frederick William the Great Elector came to power in 1640 and took charge of the faltering kingdom. He began the move toward Prussian absolutist rule by implementing taxes without the people's consent. The Estates asserted their right to vote on taxes, but were put down in both Brandenburg (1653) and Prussia (1663). Frederick William created a standing army in 1660 and turned up taxes. By 1688, the year of the Great Elector's death, a population of one million supported a thirty-thousand man strong military and state revenue had tripled.

With Frederick William gone, the weak ruler Elector Frederick III (1688-1713) ascended to the throne. He gave more attention to personal luxury than running the nation and was an admirer of France's Louis XIV, whose habits were similar. Frederick William I became king of Prussia after Frederick III's death.

Lifestyle
Frederick William I was disciplined and frugal, although slightly odd in several respects. The Hohenzollern family had been Protestant since the Reformation in the 15th century, and, though not a devout churchgoer, Frederick was morally immaculate. Unlike most monarchs of the day, he never took a mistress and remained faithful to his wife, the BritishHanoverian Sophia Dorothea. As previously mentioned, he was obsessed with the army and sought to emulate soldiers as much as possible. Most of the time he sported full military dress and often drilled Prussian troops. There are many stories about his eccentricities, including a propensity for physically striking government ministers with whom he was displeased. Most of these are probably myth, however, we do know that he created an honor guard of 1200 soldiers who were at least six feet high and were referred to as the Potsdam Guard. Frederick William I appeared to harbor a bizarre interest in tall uniformed men with big guns. When sick or depressed, he would order a contingent to march through his bedroom in the hopes that the sight of their gloriousgrandeur would improve his condition. This was the one perk he allowed for himself, as he was disgusted by rulers who enjoyed lavish lifestyles. Sophia and the king lived simply, supporting themselves with the earnings from their landholdings instead of taxes. He did not even make himself tax-exempt.

Frederick William I improved the military and reformed the government, making Prussia a formidable force in Europe. His fairness and disdain for ostentation made him popular with the people, as they were proud of their country's new strength. Frederick's son Fritz, who would come to be called Frederick the Great, succeeded him after his death in 1740. Frederick William I's training of the military would pay off during Fritz's rule, when the Prussian army fought and defeated outnumbering enemies.

Sources:
McKay, John P., John Buckler, and Bennett D. Hill. A History of Western Society. Houghton Mifflin Company: Boston, 1999.
http://www.xs4all.nl/~kvenjb/madmonarchs/fredwil1/fredwil1_bio.htm